Zinc binding to lambda phage DNA studied by voltammetric techniques

Binding of zinc to lambda phage DNA was investigated by differential pulse voltammetry and cyclic voltammetry. These methods rely on the direct monito ring of reduction and oxidation current of zinc in the absence and presence of this virion DNA. Titration graphs of Zn2+ with DNA were obtained in the concentration ranges from 3.57 x 10(-12) to 3.92 x 10(-11) mol L-1 and 6.9 7 x 10(-12) to 5.56 x 10(-11) mol L-1. These data were used to calculate th e dissociation constant of the complex and the stoichiometry. The mechanism of this reaction was studied by cyclic voltammetry through curves I (oxida tion current of Zn2+) versus v(1/2) (square root of scan rate). These curve s showed that the oxidation-reduction process of Zn2+ was not controlled by diffusion in the presence of lambda phage DNA.